Sirtuin 2 Contributes to Pancreatic Injury and Inflammation by Modulating Immediate Early Response 3–Mediated Ferroptosis in Acute Pancreatitis
TL;DR
A novel SIRT2/IER3-mediated mechanism driving ferroptosis in AP is revealed, and serum SIRT2 and IER3 were elevated in AP patients and correlated with disease severity and inflammation.
Abstract
Background & Aims Acute pancreatitis is a potentially life-threatening inflammatory disorder characterized by trypsin overactivation within acinar cells. Although sirtuin 2 is linked to inflammation, its precise role in acute pancreatitis remains poorly understood. Methods Rats were pretreated with AGK2 a (sirtuin 2 inhibitor), Ferrostatin-1 (ferroptosis inhibitor), 1α,25-dihydroxyvitamin D3 (an immediate early response 3 inhibitor), adeno-associated virus–sirtuin 2, or adeno-associated virus–short hairpin-sirtuin 2 before L-arginine–induced acute pancreatitis. RNA sequencing was performed to identify potential downstream targets of sirtuin 2. In vitro, sirtuin 2 and immediate early response 3 expression was manipulated by small interfering RNA or overexpression plasmids. The effects on ferroptosis and inflammation were assessed using Western blot, quantitative polymerase chain reaction, immunofluorescence, and assays measuring reactive oxygen species, iron (II), mitochondrial membrane potential, and lipid peroxidation. Regulatory mechanisms among sirtuin 2, immediate early response 3, and ferroptosis were further investigated using co-immunoprecipitation and dual-luciferase assays. Results AGK2 or ferrostatin-1 alone reduced pancreatic damage, inflammation, and ferroptosis, with combination therapy showing synergy. Sirtuin 2 or immediate early response 3 inhibition was protective, upregulating solute carrier family 7 member 11–glutathione peroxidase 4, reducing reactive oxygen species, iron (II), and lipid peroxides, and restoring mitochondrial function. Conversely, overexpression of sirtuin 2 or immediate early response 3 produced the opposite effects. AGK2 and 1α,25-dihydroxyvitamin D3 reversed damage from sirtuin 2 overexpression. Co-immunoprecipitation confirmed sirtuin 2 deacetylates and upregulates immediate early response 3. Luciferase assays showed immediate early response 3 transcriptionally represses solute carrier family 7 member 11. Clinically, serum sirtuin 2 and immediate early response 3 were elevated in patients with acute pancreatitis and correlated with disease severity and inflammation. Conclusions Sirtuin 2 enhances immediate early response 3 expression via deacetylation, inhibiting the solute carrier family 7 member 11–glutathione peroxidase 4 axis and promoting ferroptosis, thereby exacerbating acute pancreatitis. Serum sirtuin 2 and immediate early response 3 are potential biomarkers for acute pancreatitis severity. This study reveals a novel sirtuin 2–immediate early response 3-mediated mechanism driving ferroptosis in acute pancreatitis.